Air supplying and preheating units for boilers



United States Patent Inventor: Benjamin F. Kwiat 54 N. Pleasant Avenue, Ridgewood, New Jersey 07450 Application No.: 720,603

Filed: April 11, 1968 Patented: Aug. 4, 1970 AIR SUPPLYING AND PREHEATING UNITS FOR BOILERS 4 Claims, Drawing Figs.

U.S. Cl. 110/56, 1 10/75 Int. Cl. F23c 7/06, F231 9/00 Field ol'Search 431/158;

[56] References Cited UNITED STATES PATENTS 2,000,733 5/1935 Avery 122/149 2,923,348 2/1960 Fraser 431/158 3,265,042 8/1966 Huckabee 122/149 Primary Examiner- Kenneth W. Sprague Att0rneyRichards and Geier ABSTRACT: AirTsWmtTintcrior of a boiler through circumferentially disposed openings of a unit facing the combustion chamber of the boiler and surrounding the nozzle of the oil burner of the boiler. The unit contains deflector blades for the flowing air. Blowers connected to the motor of the oil burner may be attached to the unit to inject air into the unit. Beside the circumferential openings, tubular air supply units of known construction may be attached to the unit to further promote the flow of air.

Patented Aug. 4, 1970 3,522,779

Sheet 1 of 2 FIGI BENJAMIN E KWIAT I N VEN TOR.

Patented Aug. 4, 1970 3,522,779

Sheet 2 of 2 FIG?) 26 INVEN'TOR. J BENJAMIN F. KWIAT U.S. PATENT 3,522,779 AIR SUPPLYING AND PREIIEATING UNITS FOR BOILERS This invention relates to units supplying air to boilers while preheating the supplied air.

In my patent No. 3,280,770, issued October 25, 1966, l have described an air supply unit for boilers which consists essentially of an elongated tube located close to the oil burner and provided with inner deflector blades for the circulation of air. This unit was found to be most effective in actual practice since it saves a substantial amount of heating costs. Further experimentation has shown, however, that the heating costs of a boiler can be reduced to a much greater extent if the tubular air supply unit of the aforesaid patent is replaced by or com bined with a differently constructed unit with differently located air ejecting openings.

Consequently, an object of the present invention is the provision of an air preheater and supplier unit for boilers which will reduce smoke, soot, carbon and other pollutants, which will greatly reduce boiler maintenance and will increase burner and boiler longevity.

Another object is the provision of a unit which provides heated air creating a premix flame effect in the boiler with jets evenly distributed over the entire flame.

A further object is the provision of a unit of the described type which can be conveniently installed inside the combustion chamber of a boiler and fitted inside the front line brick wall thereof without disturbing the burner, the oil lines, the electrical lines and the like.

Other objects of the present invention will become apparent in the course of the following specification.

In the accomplishment of the objectives of the present invention it was found desirable to provide an air supplying and preheating unit capable of being installed in existing oil, gas, coal or any other fuel boilers and comprising a casing having a central opening adapted to enclose the portion of the burner extending into the combustion chamber. The surface of the casing facing the combustion chamber is provided with air emitting openings circumferentially disposed around the central opening. According to another embodiment of the invention, the air emitting openings are located in two spaced vertical planes and in a cylindrical surface joining the two vertical planes. The interior of the casing is provided with deflector blades for the circulation of air. The opposite outer surface of the casing has an opening or openings for introducing the air. According to another embodiment of the invention air blowers of known construction are attached to these outer openings for injecting air into the interior of the casing. These blowers may be operatively connected to the motor of the oil burner so that their operation starts at the time the motor is switched on. According to another embodiment of the invention one or preferably two air supply units of the type described in the aforesaid patent are connected to the casing below the central opening and extend into the combustion chamber. Then a part of the air is emitted through the circumferential openings while another part is emitted through the air supply units. This construction is particularly suitable for boilers of the fire box type. The casing of the unit of the present invention may consist of two equal halves which may be conveniently introduced separately into the boiler without disturbing its structure and then assembled within the combustion chamber.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example only, preferred embodiments of the inventive idea.

In the drawings:

FIGURE 1 is a diagrammatic view of an oil burner illustrating the location of an air supplying and preheating unit of the present invention.

FIGURE 2 is a perspective view of the air supplying and preheating unit on a larger scale.

FIGURE 3 is a section through the unit along the lines Ill-Ill of FIGURE 2.

FIGURE 4 is a perspective view of a different and simplified air supplying and preheating unit of the present invention.

The oil boiler 10 shown in FIGURE 1 is of the standard fire box type and includes a foundation 11, a main body 12, a combustion region 13 and an oil burner 14 hingedly attached to a boiler plate 15 and having a nozzle 16 extending into the combustion region.

The air supplying and preheating unit 17 of the present invention is fitted inside the front fire brick wall 18 of the boiler. It is important that the combustion region should have no other air inlets. To facilitate assembly, the unit 17 may be made of two separate halves which can be separately introduced through the usual opening into the combustion region and then interconnected inside the combustion region while being fitted to the brick wall. The installation procedure is easy and does not interfere with the boiler or any of its lines.

Obviously, if desired, the unit 17 can be made of one piece.

As shown in FIGURES 2 and 3, the unit 17 has a substantially vertical casing 19 provided with an opening 20 located in the upper part of the casing. The casing 19 may be made of any suitable material, although heat transmitting alloys are preferred. When the unit is installed, the nozzle 16 of the burner 14 extends through the opening 20, thereby providing a most effective combination between the unit 17 and the burner for heating the air.

The lower portion of the casing 19 has preferably rectangular rear openings 21 communicating with air blowers 22 of standard construction. The air blowers 22 are firmly attached to the rear wall of the casing 19 by suitable flange connections. The lower front portion of the casing 19 has preferably round openings 23 enclosed by flanges serving as connections for elongated tubular air supplying units 24. The units 24 are of the type described and claimed in aforesaid patent.

The interior of the casing 19 has spaced inclined deflector blades 25 extending from opposite walls. A portion 26 of the front wall of the casing has a series of small openings 27 disposed circumferentially around the opening 20. The front wall also has a tubular inwardly extending portion 28 constituting a continuation of the portion 26 and provided with small openings 29. The rear wall has a non-perforated tubular portion 30 surrounding the opening 20. The portions 28 and 30 are joined by an integral disc-shaped portion 31 provided with circumferentially disposed small openings 32.

As already stated, the air blowers 22 are of standard construction; they are provided with motors 33 driving fans 34 which blow air from the outside through the openings 21 into the interior of the casing 19. The motors 33 are preferably connected with the motor of the oil burner 14 (not shown), so that the air blowers are actuated at the same time as the oil burner.

As described in greater detail in the aforesaid patent, each tubular unit 24 has deflector blades 35 and carries bushings 36 which may be used to provide escape for some of the air flowing through the units.

The operation of the unit of the present invention is apparent from the above description.

After the unit has been installed and connected and when the oil burner 14 is started, the air blowers 22 will be actuated and will blow air through the openings 21 into the casing 19. A part of this air will flow through the openings 23 and the tubular units 24 being. deflected by the blades 35 and emerging into the combustion region 13 where it will mix with the fuel produced by the oil burner. The temperature of the ejected air will be further increased by compression caused by eddies produced by the deflector blades 35. Another part of the air will flow upwardly through the casing 19, will be subjected to deflection and compression by the blades 25 and will flow into the combustion region through the openings 27, 29 and 32. This air will be in direct contact with the part of the oil burner which extends through the opening 20. Furthermore, the entire unit 17 will be effectively heated by the oil burner.

Practical experimentation has shown that air emitted by the openings 27 creates a premix flame effect and is preheated up to 875 F. The heated air is evenly distributed over the entire flame.

It was found that the use of the unit of the present invention results in a saving of fuel up to 25%. Smoke, soot, carbon and other pollutants are greatly reduced, the maintenance of the boiler is greatly simplified while the life of the boiler and burner is increased.

In certain types of boilers, particularly of the so-called Scotch marine type, the use of tubular air supplying units 24 is not desired. Furthermore, the use of air blowers 22 is not always necessary, since air may flow directly through the unit I7 as the result of pressure difference inside and outside the combustion region. Finally, the arrangement of air emitting openings on three different levels may be simplified without lowering to a great extent the efficiency of the unit.

A simplified air supplying and preheating unit 17 which is also the subject of the present invention, is illustrated in FIGURE 4. This unit has a casing 19' which is similar to the casing 19 in shape but does not have any openings in the front wall. The rear wall of the casing has openings 21 communicating directly with outside air. A portion 26' f the front wall of the casing has a series of circumferential small openings 27 enclosing the large opening There are no other air emitting openings, however, and the opening 20' is enclosed by a non-perforated tubular portion 30 extending between the front wall and the rear wall of the casing. The interior of the casing 19' has deflector blades (not shown) similar to the deflector blades 25.

In this construction, air will flow as the result of pressure difference through the openings 21' into the casing 19 and up the casing being deflected by the deflector blades and leaving the casing through the openings 27. Air will be effectively heated by its proximity to the oil burner.

It is apparent that the construction of FIGURE 4 may be varied by adding thereto individual parts of the construction of FIGURE 2, such as the units 24, the blowers 22 or the perforations 29 and 32. Other changes may be'also made in the illustrated constructions within the scope of the present invention.

lclaim:

1. An air supply and preheating unit adapted to be connected to a boiler which boiler includes a combustion chamber adapted to burn an air intermixed fuel, said preheating unit comprising, in combination, a substantially vertical casing having a front wall adapted to face the combustion chamber of said boiler and also having a rear wall, the upper portion of said casing having an opening therein, the lower portion of said casing having at least one air inlet opening located within said rear wall, said casing also having a tubular portion connected to said front wall and enclosing a portion of said first-mentioned opening, said tubular portion also having first circumferential air transmitting openings, another non perforated tubular portion connected to said rear wall and enclosing another part of said first-mentioned opening, the second-mentioned tubular portion being of smaller diameter than the first-mentioned tubular portion, a disc-shaped portion integrally connecting the two tubular portions and having second circumferential air transmitting openings, and a plurality of spaced deflector blades located within the casing between the air inlet opening and the first circumferentially disposed openings.

2. A unit in accordance with claim I, wherein said casing has a tubular non-perforated portion extending between said front wall and said rear wall and enclosing the first-mentioned opening.

3. A unit in accordance with claim 1, comprising at least one air blower connected to said air inlet opening.

4. A unit in accordance with claim 1, comprising at least one tubular air transmitting unit connected to an opening formed in said front wall below the first-mentioned opening, said air transmitting unit having inner deflector blades and extending into said combustion region. 

